Flotation agent for the purification of waste waters from the paper and cellulose industries



2,989,471 Ice Patented June 201 FLOTATION AGENT FORTHE PURIFICATION OF WASTE WATERS FROM THE PAPER AND CEL- LULOSE INDUSTRIES Robert Christian Keller, Basel, Switzerland, assignor, by mesne assignments, *to Fidelity Union Trust Company, executive trustee under Sandoz Trust No Drawing. Filed May 4, 1959, Ser. No. 810,541 Claims priority, application Switzerland May 8, 1958 6 Claims. (Cl. 2'5261) The present invention relates, more particularly, to a novel composition useful in a process for the purification or clarification of waste waters from the paper and cellulose industries, with a view to recovering fibrous materials, fillers, etc. entrained by such waters.

In the purification or clarification of waste Waters from the paper and cellulose industry by flotation, the fibrous materials, fillers and the like are collected on the surface of the water in pulp separators. The separation of such materials is dependent upon many factors, such for example as the speed of throughflow, the type of fibrous material and filler, or upon the hydrogen ion concentration and the aluminum content of the Waste waters. The separation frequently is only very incomplete. This problem of complete separation has been attacked by the art and efforts have been made to improve the separation and to render it more feasible and dependable, by the addition of flotation agents. A wide variety of the latter have been proposed, but there is still considerable room left for a completely satisfactory solution of the said problem.

The object of the present invention is the embodiment of a novel group of particularly efficacious flotation agents, especially useful for the purification of waste waters from the paper and cellulose industry by the flotation process. This object is realized according to the present invention by the embodiment, as flotation agents for the aforesaid purpose, of four-component mixtures consisting of:

About 10 parts by weight of sulfonated castor oil,

5 to 25 parts by weight of unsaturated higher fatty acids, 5 to 25 parts by weight of resin acids, and

5 to 30 parts by weight of mineral oil or synthetic oil,

the mixture ingredients which contain acid groups being present in the form of their alkali metal (e.g. sodium) 7 salts.

The new flotation agents bring about rapid and complete separation of the fibrous materials and fillers in the pulp separators or collectors, and are essentially insensitive to fluctuations or variations in composition of the waste waters. The wet strength of papers, which contain the material recovered with the aid of the flotation agents of the present invention, is not unfavorably influenced thereby. Moreover, the flotation agents of the invention have no tendency to slime formation, this being in sharp contrast to glueor sizing-containing flotation agents.

The designation sulfonated castor oil" as herein employed has reference to the organic substance contained in conventional Turkey-red oils and refined Turkey-red oils, the conventional Turkey-red oils being those having preferably a sulfonation degree of 2050% and being obtainable according to known methods (of. e.g. Ullmann Encyklopaedie der technischen Chemie, vol. 9 (1932), pages 801-802), by sulfonation of castor oil with a quantity of sulfuric acid equal to 15%, 25%, 35% and more of the quantity of the castor oil.

The relation between the organic substance and the dry content of a turkey red oil is approximately 10:13.

Suitable higher fatty acids are for example oleic acid, ricinoleic acid, linoleic acid, linolenic acid or mixtures of such acids, e.g. such mixtures as are present for example in tall oil or in vegetable oils.

As resin acids, there are suitable for example abietic acid, neo-abietic acid, dihydroabietic acid, tetrahydroabietic acid, dehydroabietic acid, dextro-pimaric acid and isodextropimaric acid or mixtures of such acids, e.g. such mixtures as are present for example in colophony (rosin) or in tall oil.

If tall oil, which consists essentially of a mixture of unsaturated higher fatty acids and resin acids, is used as a starting material, this oil has to be taken in such a quantity, that the relation between the fatty acids and resin acids in the flotation agent remains within the limits indicated above.

Suitable mineral oils for the purposes of the present invention are the hydrocarbon fractions obtained in the refining of petroleum (crude oil) and having boiling points in the range between 150 and 450 C. (760 mm.) or in an intermediate range. within these limits, such for example as those commercially known as spindle oil, machine oil, cylinder oil, diesel oil, gasoline, gas oil, paraflin oil and white spirit. Also suitable are synthetic liquid hydrocarbons obtained by the Fischer-Tropsch synthesis and boiling within the aforesaid range.

In using the preparations according to the invention, it is preferable first to prepare concentrated aqueous stock solutions containing for example 0.5 to 5% by weight of flotation agent according to the present invention, and to add such stock solution at a point anteriorly of the separator or collector in a quantity of for example 3 to 50 grams of flotation agent per cubic meter of waste water.

The following examples set forth presently preferred exemplary embodiments of the invention. Parts and percentages are by weight; temperatures are in degrees centigrade.

Example 1 An admixture is made of parts of spindle oil [specific gravity (20) 0.918, viscosity (20)"54.7C;P., boil- .ing range 320-400], 200 parts of distilled tall oil containing 30% of resin acids (acids number=l90; saponification number=l9l; iodine number=l60; unsaponifiables=2.0%), and parts of commercial Turkey-red oil obtained by sulfonation of castor oil with.2030% of the weight of the castor oil of sulfuric acid of 96% strength and containing a total fatty acid content of 62.5%. There results an homogeneous, brown, oily liquid,

which is clear at room temperature (about 2030), and

which can be used as follows:

12 parts of sodium hydroxide are preliminarily dissolved in 250 parts of water. 100 parts of the liquid prepared according to the preceding paragraph are then added in the form of the above-mentioned aqueous stock solution obtained by dilution of the aforesaid amount of liquid with water to a concentration of about 0.5 to 5% by Weight of flotation agent, to the resultant clear solution. The so-diluted solution is continuously added to the waste water being clarified, anteriorly of the separator for the fibrous material and filler, at a rate of 500 to 2500 milliliters per cubic meter of waste water.

Example 2 225 parts of commercial Turkey-red oil with a total fatty acid content of 50% obtained by sulfonating castor oil with 50% of the weight of the castor oil of sulfuric acid of 96% strength, 280 parts of distilled tall oil containing 30% of resin acids, and 260 parts of naphthenebased, acid-refined mineral oil [specific gravity 0.922 (20), viscosity (50)=2.1 Engler, flame point=, boiling range 250-330"] are admixed. The water originating from the Turkey-red oil is removed by vacuum distillation. There is obtained a brownish oil, which is non-freezing, and which can be used as a flotation agent after the manner described in the last paragraph of Example 1.

Example 3 25 parts of olein [saponification number=202; iodine number=93; specific gravity (20)=0.89], parts of rosin (saponification number=l66; melting range 80 90), and 13 parts of Turkey-red oil (dry content 77%) having a 62.5% fatty acid content (as in Example 1) are homogeneously admixed with 30 parts of mineral oil [specific gravity (20)=0.895; viscosity (20)=6.62 Engler; flame point=160; solidification point below --40, boiling range 290360]. The water originating from the Turkey-red oil is removed by vacuum distillation.

The so-obtained oily preparation possesses good flotation action when it is admixed, in accordance with paragraph 2 of Example 1 with dilute aqueous caustic alkaline solution suflicient to neutralize all acid groups, and then added to the waste waters to be clarified after the manner described in Example 1.

Example 4 The procedure according to Example 3 is repeated, i.e. the identical ingredients are employed but in the following proportions:

Parts Olein 5 Rosin 5 Turkey-red oil 13 Mineral oil 5 The product is a flotation agent, useful for the purposes of the present invention in the manner described in Example 1.

Example 5 The procedure according to Example 3 is repeated, i.e. the identical ingredients are employed but in the following proportions:

Parts Olein 5 Rosin 25 Turkey-red oil 13 Mineral oil 5 tions obtained by the Fischer-Tropsch synthesis and boiling within the previously indicated ranges.

Having thus disclosed the invention, what is claimed is:

l. A flotation agent for the separation of fibrous materials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of about 10 parts by Weight of sulfonated castor oil, 5 to 25 parts by weight of unsaturated higher fatty acids, 5 to 25 parts by weight of resin acids, and 5 to 30 parts by weight of hydrocarbon oil having a boiling point in the range between 150 and 450 C. at 760 mm. pressure.

2. A flotation agent for the separation of fibrous materials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of parts by weight of spindle oil, 200 parts by weight of tall oil containing 30 percent by weight of resin acids, and parts by weight of Turkey-red oil.

3. A flotation agent for the separation of fibrous materials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of 225 parts by weight of Turkey-red oil, 280 parts by weight of tall oil containing 30% by weight of resin acids, and 260 parts by weight of mineral oil.

4. A flotation agent for the separation of fibrous materials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of 25 parts by weight of olein, 5 parts by weight of rosin, 13 parts by Weight of Turkey-red oil, and 30 parts by weight of mineral oil.

5. A flotation agent for the separation of fibrous mate rials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of 5 parts by weight of olein, 5 parts by weight of rosin, 13 parts by weight of Turkey-red oil, and 5 parts by weight of mineral oil.

6. A flotation agent for the separation of fibrous materials and fillers from the waste waters of the paper and cellulose industry, which consists of a mixture of 5 parts by weight of olein, 25 parts by Weight of rosin, 13 parts by weight of Turkey-red oil, and 5 parts by weight of mineral oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,968,876 Crago et al. Aug. 7, 1934 2,347,147 Booth Apr. 18, 1944 2,682,337 Hodges et a1 June 29, 1954 2,729,334 Schwarz et al. Jan. 3, 1956 

1. A FLOTATION AGENT FOR THE SEPARATION OF FIBROUS MATERIALS AND FILLERS FROM THE WASTE WATERS OF THE PAPER AND CELLULOSE INDUSTRY, WHICH CONSISTS OF A MIXTURE OF ABOUT 10 PARTS BY WEIGHT OF SULFONATED CASTOR OIL, 5 TO 25 PARTS BY WEIGHT OF UNSATURATED HIGHER FATTY ACIDS, 5 TO 25 PARTS BY WEIGHT OF RESIN ACIDS, AND 5 TO 30 PARTS BY WEIGHT OF HYDROCARBON OIL HAVING A BOILING POINT IN THE RANGE BETWEEN 150 AND 450*C. AT 760 MM. PRESSURE. 